Variable speed transmission



Aug. 19, 1958 z. v.-wE|sE| v 2,847,861

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VARIABLE SPEED TRANSMISSION Original Filed June 25, 1953 6 Shets-Sheet 2IN VEN TOR. X51/A5 K/.ia

Aug. 19, 1958 z. v. wElsEL 2,847,861

VARIABLE SPEED TRANSMISSION Original Filed June 23, 1953 6 Sheets-Sheet3 OIL. INLET T0 5 UMP IN VEN TOR. [5A/45 1./ l/551.

Mier/2 e ys Z. V. WEISEL VARIABLE SPEED TRANSMISSION Original Filed June23. 1955 Aug. 19, 195s l m 313 ga/ 6 Sheets-Sheet 4.

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Aug. 19, 195s z. v. wElsEl. t VARIABLE SPEED TRANSMISSION original FiledJune 25, 1955 e sheets-sheet 5 INVENTO'R. 22u/A5 1./ WM5/ BY l I lom'eyAug. 19, 1958 z. v. wElsEl. 2,847,861

VARIABLE SPEED TRANSMISSION original Fiied June 2:5, 1953 6 Sheets-Sheet6 INVENToR. ZAM/45 1./ Meme/ United States Patent VARIABLE SPEEDTRANSMISSION Zenas V. Weisel, Los Angeles, Calif.

Original application June 23, 1953, Serial No. 363,606,

now Patent No. 2,748,614, dated June 5, 1956. Divided and thisapplication September 13, 1955, Serial No. 534,139

13 Claims. (Cl. 74-190.5)

This is a division of application Serial No. 363,606, filed by me June23, 1953 and issued lune 5, 1956, as Patent No. 2,748,614. ApplicationSerial No. 363,606 is a continuation-in-part of application Serial No.175,695, filed by me July 24, 1950.

The present invention relates generally to transmissions and moreparticularly to an improved high speed transmission especially suitablefor use in aircraft.

Modernly, there exists a need for a transmission adapted to connect apower source having a variable speed to a driven member which mustrotate at a substantially constant speed despite variations in the loadimposed thereon. One example lies in the driving of aircraftalternators. If a transmission is to be used in aircraft, it mustadditionally be light in weight, compact, and foolproof. Moreover, itmust be capable of transmitting a high percentage of driving power intouseful work over the wide speed range at which the power source mayrotate. The primary purpose of the present invention is to provide anovel transmission embodying all of these qualities.

A major object of the present. invention is to provide an improved highspeed, continuous, variable ratio transmission.

It is a further object of the present invention to provide atransmission incorporating complementary driving and driven discsdefining opposed surfaces of revolution, which discs are bridged by oneor more power-transmitting, conically-profled rollers.

Another object is to provide a transmission of this nature which is veiyeicient at all speeds and under all load conditions.

It is yet a further object of the present invention to provide a noveltransmission of this nature having novel means for preventing slippagebetween the discs and the rollers. i

Another object is to provide a transmission of this nature whereintracking of the rollers on the discs is insensitive to deflections,differential expansion, tolerance variations in machining and tovariations in power load.

Yet an additional object of the invention is to provide a transmissionwhich is very compact and yet is capable of transmitting a large loadover an extended period of time without requiring attention.

A further object is to provide a transmission utilizing wide-facedconoidal rollers which require the minimum roller-todisc loading forcerelative to traction force.

These and other objects and advantages of the present invention willbecome apparent from the following detailed description when taken inconjunction with the appended drawings wherein:

Figure 1 is a longitudinal vertical sectional view of a transmissionembodying the present invention and including the air cooling systemthereof;

Figure 2 is a reduced transverse vertical sectional view of saidtransmission showing the air cooling system and roller mounting thereof;

2,847,861 Patented Aug. 19, 1958 ICC Figure 3 is an elevational view ofthe input side of said transmission;

Figure 4 is an elevational View of the input side of the driving discmember of said transmission;

Figure 5 is an enlarged fragmentary detail taken approximately on theline V`V of Figure 4;

Figure 6 is an enlarged fragmentary detail taken on line Vl-VI of Figure4;

Figure 7 is a longitudinal vertical sectional View through atransmission generally similar to that shown in Figure l, illustrating aform of lubricating system which may be utilized therewith;

Figure 8 is an enlarged sectional View of an alternate form of rollermounting;

Figure 9 is a longitudinal sectional view of another form oftransmission embodying the present invention;

Figure 10 is a vertical sectional view illustrating the roller mountingutilized in the transmission of Figure 9; Figure 1l is a fragmentaryvertical sectional view taken on line XI--XI of Figure 9;

Figure 12 is an enlarged vertical sectional view of a detail of Figure9;

Figure 13 is a fragmentary enlarged View of the encircled portionXIII-XIII of Figure 9;

Figure 14 is an exploded and enlarged view of a Variable torque controldevice utilized with the transmission shown in Figure 9;

Figure l5 is an enlarged horizontal sectional view taken on line XV-XVof Figure 14;

Figure 16 is a sectional view taken on line XVI-XVI of Figure 14;

Figure 17 is a perspective View of a scooping nger utilized in thetorque control device of Figure 14;

Figure 18 is a view similar to Figure 14, but showing another type ofvariable torque control device which may be utilized with thetransmission shown in Figure 9; and

Figure 19 is a reduced vertical sectional View taken on line XIX-XIX ofFigure 18.

Referring to the drawings, and in particular, to Figure 1 thereof, thereis shown a right-hand end plate 10 having a frusto-conical portion 12with a bearing liange 14 extending inwardly therefrom. The flange 14supports a ball bearing assembly 16, and this bearing assembly rotatablysupports a rotary cam plate 18. Disposed in the center of the plate 18,as shown at 20, is a stub shaft 22 having a keyed outer portion 24adapted for driving connection with a suitable source of rotary power.

The cam plate 18 is provided with a ball channel 26 1n which a series ofballs 28 are located. The balls are retained with the aid of acomplementary ball channel 30 in the input or outer side of a rotaryinput member or' disc 32 having an outwardly directed flange 34containing a bearing ring 36 which rides upon the balls 28.

The input disc 32 has a peripheral sealing ring 38 which bears against astationary containing ring 40, the latter having a radial ilange 42connected by a series of bolts 44 to the end plate 10.

The left-hand side of the rotary input disc 32 is provided with aconcave surface of revolution 46 which may approximate a toric section.The structure is provided with a left-hand end plate 48 which issuitably connected by bolts 50 to an end ring 52 which lies in theleft-hand portion of a cylindrical casing member 54. The right-hand endplate 10 has its bolts 44 threaded into a connector ring 56 which issuitably connected as by welding to the right-hand end of thecylindrical casing 54.

The left-hand plate 48 supports a ball bearing assembly 58 which, inturn, rotatably supports an output or driven disc 60. The disc member 60is provided with a concave surface of revolution 62 which definesgenerally a toric section. Its profile may be approximately the same asthat of driving disc member 32.

Interposed between the driving and driven disc members 32 and 60 are aplurality of power-transmitting conically profiled rollers 64; eachroller having a convex surface of revolution 66. It is preferred thatthe conical profile surface 66 of the rollers 64 have a smaller radiusthan the profile surfaces 46 and 62 of the disc members 32 and 60.

The cam plate 18 and the driving disc member 32, with their ball grooves26 and 30, respectively, are so constructed that increased torque on thedrive shaft 22 will effect an increased axial pressure on the drivingdisc member 32, urging it toward the driven disc member 60. The ballchannel 26 in the cam plate 18 is constructed similarly to the ballchannel 30 in the driving disc 32; the latter being illustrated indetail in Figures 4, 5, and 6. In Figure 6, it will be seen that thebottom of the channel 30 has alternating high spots 68 and low spots 70connected by inclined cam surfaces 72. When the cam plate 18 has torqueapplied thereto, the balls will tend to ride up the slanted cam surfaces72 on the cam plate, as well as those of the driving disc member 32,thereby increasing the pressure of the driving disc member 32, againstthe rollers 64 and through said rollers to the driven disc mem; bei' 60.The rollers are so mounted on spherical pivot 76 and trunnion 82 thatthey are free to pivot on 76 and to move in the general direction of theaxes of the disc members so that substantially all of the force appliedto the rollers at their point of contact with the driving disc member istransmitted to their point of contact with the driven disc member. Whenthe torque is reduced, the balls 28 will tend to move toward low spots70 and thereby reduce the above-mentioned pressure. Pre-loading of thecam plate 18 toward the driving disc member 32 may be provided by meansof a Belleville-type dished pre-load spring 71.

The power-transmitting rollers 64 are each formed with an open centralportion mounting a ball bearing unit 72'; the inner portion of whichcarries a bearing cup 74. Located in the cup is a large ball 76 and aplurality of considerably smaller ball bearings 78 which are placed inthe cup after the large ball 76 has been disposed therein so as to coverthe surface thereof and thereby provide multiple point contacttherewith. Extending into the open top of the cup 74 is a thrust member80, the radially inner end of which has a surface formed as a portion ofa sphere for contacting the small ball bearings 78. The upper portion ofthe thrust member 8G is formed with external threads in order that itmay be threadedly secured to a trunnion shaft 82, as shown in Figure 2.Cylindrical housings 86 are rigidly secured to the main housing member54. The ends of the trunnion shaft S2 extend through stationarypartitions 90 in the cylindrical housings 86 and are provided withadjusting nuts 92 by means of which the trunnion shaft may be shiftedlongitudinally to properly center the power-transmitting roller 64relative to the axis of rotation of the concave surfaces of revolutionof the driving and driven disc members 32 and 60. The ends of thetrunnion shaft 82 may be supported by needle bearings mounted incylinders 86.

Extending from each of the bearing cups 74 in the rollers 64 is a rolleractuating control or tilting arm 94 whose outer end is provided with aball 96 which is housed within a cylindrical housing 9S welded on theside of a control ring 100. The control ring liti@ is coaxial with theinput and output discs 32 and 60, and is provided with externalperipheral teeth 102 which mesh with teeth on a pinion 104, which latterpinion is also engaged with a pinion 106 secured to the shaft of asuitable servomotor 108. This servomotor should be able to provide quickstarts and stops in combination with accurate stopping position. Theservomotor mechanism is adapted to be controlled by means of a rotaryshaft 119 which extends upwardly through the cylindrical main housing 54and rigidly mounts a friction drive wheel 112, which drive wheel is inconstant engagement with the concave surface 62 of the driven discmember 6i).

The preferred form of air cooling system is shown in Figures l, 2, and3, and includes an inlet 114 which communicates with a divided supplymanifold 116 extending downwardly about the casing 54. Air inletapertures 118 i and 120 are formed in the wall of the housing S4, tointroduce air into conduits 122 which lead radially inwardly to acentral manifold 124. The manifold 124 is open at both ends and is in owcommunication with hollow hub portions 126 and 123 of the driving anddriven disc members 32 and 60, respectively. The manifold 124 isstationary and is in coaxial alignment with the hollow hubs of thedriving and driven disc members 32 and 60. Sealing rings 130 and 132 areinterposed between each end of the manifold and the respective hubs ofthe driving and driven disc members. Radially extending air passages 134and 136 connect the hollow hub portions 126 and 12S with the outerportions of the driving and driven disc members, which passages lieclosely adjacent their respective concave surfaces of revolution 46 and62. Hence, the input and output disc members serve as integralcentrifugal pumps for creating a pressure differential that drawscooling air inwardly through conduits 122 and expels such air throughapertures 138 and 140, and no special air pumps or fans are required forefficient cooling of the transmission. With this arrangement, thesesurfaces may be effectively air cooled. Air flowing through the passages134 and 136 is exhausted through the right-hand end plate 10 by means ofapertures 138 and apertures 140 formed in the left-hand end plate 4S.

In Figure 7, there is disclosed a lubricating system and disc membercooling system which may be utilized in connection with a slightlydifferent general structural arrangement of the main casing. The casing144 is shown as having an integral left side wall 146 and a removableright side wall 148. The driving and driven disc members 32 and 60 aresubstantially identical to those shown in Figure l, as are thepower-transmitting rollers 64 and their component parts.

The lower portion of the casing 144 includes an oil inlet 150, the innerend of which conduit has an upwardly extending oil line 152 connectedthereto provided with oppositely extending cross-arm sections 154. Thesecrossarm sections 154 are provided with outlet apertures 156, and itwill be seen that the cross-arm sections extend into the hollow hubs ofthe driving and driven disc members 32 and 60. Radiating from the hollowhub portions are lubricant conduits 153 and 160 formed in disc members32 and 60. With this arrangement, the conduits 15S and 160 will convey acooling llow of oil in heat-transferring relationship with the discmembers at points adjacent the traction surface thereof so as todissipate the heat losses resulting from the contact between the rollersand the disc members. The cooling oil, however, is not permitted to liowover the engaging surfaces of the rollers and disc members whereby thedanger of a build-up of oil in front of the contacting rotary surfaces46, 62, and 66 of these elements is eliminated. Such a build-up isespecially to be avoided because of the comparatively large width ofthese contacting rotary surfaces, as will be discussed more fullyhereinafter.

A lubricant flow passage is formed by a space 162 between adjacent faceportions of the cam plate 18 and the driving disc member 32, permittingflow of lubricant to the thrust transmitting balls 28 and thenceoutwardly at the point 164 into a space 166 inside of the end plate ateach end of the housing 144. The right end plate 148 is provided with anoil drain outlet 163 leading to a suitable sump in an outer casing (notshown). The left end plate 146 defines an oil drain aperture 170 withthe lower edge of the driven disc member 60 to permit the lubricant toflow through an opening 172 into the sump or other receiving meansprovided therefor;

An oil passage 174 extends through the cam plate 18 adjacent its centralportion and communicates with a radial passage 176 so as to providelubricant for the ball bearing assembly 16 in which the cam plate 18 isrotatably mounted. When oil flows through the ball bearing assembly 16,it is conducted through a small port 178 so as to communicate with theoil ow passage 162. A branch oil flow space is defined between the outerportion of the bearing assembly 16 and a part of the cam plate 18. vThisspace iscontinued as shown at 182 between an outer portion of the camplate 18 and a ange 184 formed on a bearing assembly ring 186, whichring fits into a large central opening in the right end plate'148. Aconventional lubrication arrangement may be provided for the rotarysupport of the driven disc member 60, including lubricant passages 188which provide oil for the bearing assembly 58. The lubricant inletconduit 150 includes a branch 190 provided with outlet apertures 192adapted to spray lubricant over the exterior of the servomotor 108. Thislubricant drops into a suitable sump referred to above, but not shown inthe drawing.

It should be noted that the servomotor control shown in Figure 7 dilferssomewhat from that shown in Figure 1. The servomotor 108 in Figure 7mounts a wheel 194 on its main shaft, which wheel is in frictionalcontact with a wheel 196 supported on a stub shaft 198; the latter beingcarried by the left housing wall 146. The wheel 196 is in frictionaldrive contact with the peripheral edge of the driven disc member 60.

In both the embodiment of Figure 1 and that of Figure 7, an internallysplined sleeve 200 is shown coaxially mounted in the center of thedriven member 60. This sleeve is adapted to be drivingly connected witha constant speed unit which, in the case of an aircraft, maiI be analternator, although this specific use is, of course, not intended tolimit the application of the invention.

In Figures l, 2, and 3, there is shown lubricating means which may beutilized in addition to that shown in Figure 7. A certain amount oflubricant is contained within the cylindrical casing 54. Located in thelower medial portion of the casing are capillary wicks 246 and 248 whichare adapted to conduct smallamounts of lubricant upwardly from thebottom of the casing. As

. shown in Figure 2, the wick 246 extends upwardly in two directionsfrom the bottom of the housing 54 and thence radially inwardly as shownin Figure 3, to extend partially around the hollow driving shaft 22. Thewick 248 extends upwardly in the housing 54 to wipe against the innerportion of the concave surface 46 on the driving disc member 32.Similarly, a wick 250 extends from the lower portion of the housing 54to the outside of the internally keyed sleeve 200 in the driven discmember 60. This wick-type oiling system automatically meters therelatively minor amount of oil required for lubrication of the tractionsurfaces of the rollers and disc members, as well as the ball bearings,and limits the quantity of oil splashed into these traction surfaces.This system is particularly applicable to the form of transmission shownin Figure 1. It should be noted that by the utilization of suchwick-type oiling system, the need of a special oil pump and theaccessories thereof is eliminated.

It will be observed that the rollers 64 and the disc members are formedwith spirally extending grooves 242 and 244, respectively, on theircontacting surfaces. These grooves 242 and 244 serve to prevent theoccurrence of a power loss at high rotational speeds of the discs androllers resulting from the build-up of lubricant in front of thecontacting rotary surfaces 46, 62, and 66, of these elements. Withoutthis grooving such build-up of lubricant on these surfaces may form awedge which tends to effect the separation of the rollers relative tothe discs. When such grooving is utilized, however, the trappedlubricant has only to flow a short distance along the con'- tactingsurfaces into a groove. It has been determined that the depth of thegrooves may be very shallow and in Figures l, 2, 7, and 9, their size isexaggerated in the interest of clarity. Although this grooving is shownas having a spiral conguration in order that it may impart a pumpingaction to the lubricant, the grooves may instead be formed as aplurality of axially-spaced circumferential grooves.l Moreover, thegrooving may be formed on the rollers alone, while the contact faces onthe disc members are made smooth. It should likewise be particularlynoted that although such grooving is especially adapted for use inconjunction with a transmission of the type disclosed herein, it mayalso find use in other applications involving rapidly rotatingcontacting rotary surfaces.

In Figure 8, there is illustrated a modified form of mounting for therollers 64. Each of these rollers 64 and bearing assemblies 72 isgenerally similar to those shown in Figure 1. The bearing assembly iscarried on a reduced portion of an upwardly convexly shaped bearingsupport 270, while a concave cup 274 is positioned above the bearingsupport. The position of the center of the radius of curvature of theconvexly shaped portion of the bearing support 270 and of the concaveportion of the cup 274 should be located -on the axis of rotation ofroller 64 and should preferably lie in or near the plane containing thecenter of contact of this roller with the driving and driven discmembers 32 and 60. The bearing support 270 and the cup 274 conne aplurality of relatively small ball bearings 276. The cup 274 issupported by a threaded spindle 278 and may be mounted in the trunnionshaft 82 in the same manner as the firstdescribed power-transmittingroller mounting. Preferably, however, the cup 274 and spindle 278 willbe made integral with the cross-arm 82.

In operation, the input shaft 22 is adapted to Ibe connected to a rotarysource of power whereby it may rotate the cam plate 18 and driving discmember 32. Rotation of the latter member effects concurrent rotation -ofthe rollers 64 and hence of the driven disc member 60. The latter discmember in turn rotates the internally keyed sleeve 200 so as to drive anaircraft alternator, or the like. For effective use, such an alternatormust be driven at a substantially constant speed. It is contemplatedthat so long as the driven disc member 60 rotates at a constant speed,the servomotor will remain stationary. If, however, the driven discmember 60 has its speed of rotation reduced, the servomotor mechanismwill operate to partially rotate the control ring and thus shift theroller actuating control arms 94. This in turn causes a tilting of eachof the rollers 64 about an axis in a plane containing the axes ofrotation of the driving and driven disc members 32 and 60, said axispassing through the center of the Contact of each roller with thedriving disc and the center of contact of the roller with the drivendisc. The transmission shown in Figure 1 is adapted for acounterclockwise direction of rotation of its input shaft 22 when viewedfrom the front or input side thereof. If the roller actuating arms 94are raised from the position of Figure 1, it will cause the rollers 64to move in a spiral direction relative to the profiles of the concavefriction surfaces 46 and 62 on the disc toward the dotted line position252 of Figure 1. The rollers 64 will each ride outwardly on the concavesurface of the driving disc member 32 and inwardly on the concavesurface of the driven disc member 60 during such movement. During thismovement of the rollers, the loads carried theret by continue to becarried by the trunnion shaft 82; these shafts rotating about theirlongitudinal axes within the bearings mounted in the fixed cylinders 86.This will increase the speed of the output member 60 until it has againreached the proper speed.

When the roller actuating control arms 94 areV each 7 tilted asmentioned, the relative arrangement of each arm to the `ball 76 in theroller cup 74 and also relative to the roller trunnion shaft 82 is suchthat for a predetermined degree of tilt of the control arm 94, eachroller 64 will move to a definite ratio position and reach a point ofequilibrium in a plane normal to the axis of the roller thrust member80. As a result, it will be seen that the device will act promptly andaccurately in response to movement of the servomotor mechanism and thatthis mechanism will move in response to fluctuations in speed of thedriven disc member 60.

During operation, assuming the driven sleeve 280 is connected to adevice such as an alternator, if a sudden increase in the power loadoccurs, it will require that an increase in torque be supplied by thepower source to the input shaft 22. Under such conditions, the cam plate18 will tend to rotate relative to the driving disc member 32, causingthe cam balls 28 to ride up the incline 72 in their Vball grooves 26 and30, and impart a greater axial thrust on the disc member 32. Thiscreates greater compressive forces between the driving and driven discmembers 32 and 60 relative to the convex surface 66 of each roller 64 topermit each roller to transmit the increase in traction force requiredby the additional torque without slip at the traction surfaces. When thepower load returns to normal, the torque input may be reduced to normalagain so that there is then a reduced thrust imparted by the cam plate18 whereby the cam balls 28 may roll down the incline 72 and thus imparta reduced axial thrust on driving disc member 32. This serves to reducethe compressive forces between the rollers 64 and the disc members 32and 60 so as to improve the overall efficiency of the device at partload and to permit its parts to have a longer service life.

In this regard, it should be particularly noted that the radius of theprofile surface 66 of each roller 64 is less than the radius of theprofile surfaces 46 and 62 of the disc members 32 and 60. Accordingly,during such part load conditions, the contact path between the rollersand the discs is relatively much narrower than when under full powerload, and hence the departures from true rolling which occur in thecontact path and which produce a certain amount of friction power lossand some heat are considerably reduced over that for full power.Additionally, since this contact path is narrower at part load, thepower loss resulting from the build-up of oil in front of the contactingrotary surfaces 42, 62 and 66 will be less than at full load. Since thisis true, wear between these surfaces will be at a minimum. Under full ornear-full load conditions, however, it has been deteri mined that theroller surfaces 66 will actually deform so as to approximate thecurvature of the disc surfaces 46 and 62 by virtue of the increasedaxial thrust imparted upon the driving disc 32. Because of suchdeformation, it would be undesirable to have the radius of the profilesurface 66 of the rollers 64 equal to the radius of the profile surfaces46 and 62 of the disc members 32 and 60. This is true since even veryslight deflection of these parts under 'an increase in load and/ or adifferential temperature expansion could cause the contact of theseveral rollers with the disc members to occur at different points onthe disc members. Additionally, the contact point of an individualroller could exist at different points on each disc member. The effectof such conditions would be an increased power loss, increased stress,and indefinite control over the rollers. The practical difficulty ofmachining and fabricating the transmission if these radii were equal,will also be evident.

Referring now to Figures 9 through 17, there is shown another form oftransmission em'bodying the present invention, which transmissionbroadly comprises a cylindrical casing 250 wherein are mounted an inputshaft 252 adapted to rotate an input disc member 254, an output shaft256 adapted to be rotated by an output disc member 258, and a pluralityof power-transmitting conically profiled rollers 260 having a convexsurface of revolution 262. The radius of the surface 262 of each rolleris less than the radius of the profile surfaces 264 and 266 of the discmembers 254 and 258, respectively. The output or driven shaft 256 isformed with splines 268 for receiving the shaft of an aircraftalternator, or the like (not shown). Each of the rollers 260 issupported by a trunnion shaft 270 that is rotatable about itslongitudinal axis when the roller is tilted by means of a tilting arm272. The tilting of these arms is in turn effected by a control ring 100which is connected to cylindrical housings 98 and to a servo motor (notshown) in the same manner as set forth with regard to the transmissionshown in Figure l or in Figure 7. It is contemplated, however, that,other types of speed-sensing mechanisms may be utilized for controllingthe control ring 100.

As shown in Figure l1, the ends of the trunnion shafts 270 are disposedwithin fixed cylinders 276 and needle bearings 278 permit relativerotation therebetween. Adjustment of the shaft 270 with respect to thesecylinders 276 may be effected by means of a pair of pusher elements 279coaxially slidably carried within these cylinders, such pusher elementsincluding threaded rods 280 supported within rings 282 and mounting locknuts 284. The mid-portion of each trunnion shaft 270 is formed with abore at 286 to slida'bly receive the outer end of a thrust member 288.An adjustment stud and nut combination 290 is mounted by each trunnionshaft for obtaining the proper adjustment of the thrust member 288relative thereto.

Referring to Figure l2, the thrust member 288 is coaxially disposedwithin a thrust cup 292, which cup is in turn coaxally encircled by theroller 260. The radially inner end of the thrust member 288 is formedwith a iiange 294 having spherically curved sides 296 adapted to bearagainst radially inner side wall 298 of the thrust cup 292. The radiallyinner end of the thrust member is formed with a cavity 300 having agenerally fiat end wall 302. A pivot element 304 is disposed against theend wall 306 of the cup 292 so that its center portion 308 may bearagainst the end wall 302. This center portion 308 is spherically curvedas indicated at 310 whereby there is provided a substantiallyfrictionless pivot point between the thrust member 288 and the thrustcup 292. With this arrangement, during movement of the tilting arms 272to change the ratio position of the rollers 260, the thrust cups 292,and hence the rollers 260 may undergo pivotal movement independently ofthe thrust members 288. In this manner, the rollers 260 are free tospiral to their new position even though the required amount of radiallyinwardly directed force is being applied thereto by means of the thrustmembers 288.

As indicated in Figure 13, only the rollers 260 are formed with oilrelief grooves 242 in this form of the invention, the contact faces ofthe input and output disc members being smooth.

As shown in Figure 9, the rollers 260 are rotatably supported by a pairof axial thrust type ball bearings 310, the inner peripheries of whichencircle the thrust cups 292. The outer portion of each thrust cup isformed with a spirally curved groove 312, whereby an oil conductingpassage 313 is defined when the ball bearings and thrust cups areassembled. The lower end of this passage 313 is connected to the insideof the thrust cup below the thrust member ange 294 by a short bore 314.This portion of the thrust cup cavity is in turn in communication withan axial bore 316 extending through the thrust member 288 by auxiliarybores 318. Referring to Figure l1, the thrust members axial bore 316receives oil by means of a cavity 318 formed in one side of the trunnionshaft 270 and transverse bores 320 formed in the thrust member; thecavity 318 being connected by a branch to oil line 334. `O-rings 324,326, and 328 may be provided for sealing the circulated oil.

The oil entering the lower end of the passage 313 will be urged radiallyoutwardly therethrough during operation of the device. The upper oropposite end of passage 313 empties into a passage 330 formed throughthe center of the tilting arm 272. This latter passage 330 empties intothe main housing out of communication with the roller path. The oil line334 encircles the interior of the casing 250 and receives oil underpressure from an oil pump (not shown) mounted at the bottom of thecasing and driven by the shaft 274. With this arrangement, the bearings310 may be provided with a'cooling agent that follows a closed path andhence will not come into contact with the contact surfaces of therollers and the disc members. The oil circulated through the casing maybe cooled by contact with the upper cooling ns 336, such oil beingconducted thereto by a manifold member 338, as shown in Figure 9. Atachometer 34) driven by a shaft 342 is shown mounted at one side of thecasing 250.

Referring again to Figure 9, the front end of the casing 250 is formedwith a bore 344 wherein is mounted a bearing retainer cup 346, which cupin turn receives the outer race of a front ball bearing 348. The outerperiphery of this cup 346 may be supplied with a cooling tluid, such asoil, by means of a conduit 350. The inner race of the ball bearing 348encircles the front portion of a drive sleeve member 360, which lattermember is formed with a blindbore 362. A plurality of free-wheelingsprag elements 364 are circumferentially arranged within the annularspace separating the inner periphery of the blind bore 362 and the outersurface of the input shaft 252. These sprags are retained in thisannular space by snap rings 365 and 366. The rear portion of the drivesleeve member 360 is of larger diameter than the front portion thereofand is formed with multiple spiral grooves defining a double thread 368.The input disc member 254 is formed with a complementary multiple spiralgroove defining a double thread 370 whereby there is defined a spiralball channel 372 wherein are disposed a plurality of balls 374.

As shown in Figures 14 through 16, the starting point of one thread ofthe double thread 370 is joined to the end of the other thread by across-over notch 376 which is in part dened by a pair of scoopinglingers 378. These scooping ngers 378 may consist of curved rods thatare secured to the input disc member 254 by means of bolts or screws380. With this arrangement, if the input shaft 252 and hence the drivesleeve member 360 is rotated in a counterclockwise direction whenv-iewed from the front,

the balls 374 will also tend to roll in the channel 372 in acounter-clockwise direction until they reach the crossover notch 376.Since, as shown in Figure 16, this notch is deeper than the remainder ofthe ball channel 372 formed in the input disc member 254, the balls willroll outwardly sufiiciently to be able to move up over the rib 382between the two threads of the double lead thread 370 whereby they willbe free to recirculate through the channel. During movement of the ballsthrough the cross-over notch 376, the scooping fingers 378 provide asurface having a gentle curvature for guiding the balls through thenotch. The ends of the scooping fingers may extend over the ends of thecross-over notch. The balls 374 will be free to continue to move slowlyor walk around the ball channel 372 as long as the input shaft 252 isbeing rotated. Hence, these balls will not remain in any one positionfor an appreciable period of time, and accordingly they will not causepitting of the walls of the ball channel during normal operation. If asudden above normal load is imposed upon the alternator (and hence thedriven disc member 258) whereby an increase in torque must be applied tothe driving disc member 254, the balls will roll between the grooves 368and 370 so as to screw the driving disc member to the left so as toincrease the pressure of the driving disc member against the rollers 260and through said rollers to the driven disc member 258. Inasmuch as theballs travel through the channel 372 with a random movement, there islittle chance they will be disposed at the same given spot therein forany suddenly applied, above normal load. Hence, these balls will notcause a pitting of the walls of the channel when a sudden load isapplied. A flexible, dished disc-type spring 385 provides pre-loading:of the drive-sleeve member 360 toward the input disc member 254, asshown in Figure 9. With the aforedescribed arrangement, a single ring ofballs 374 may be employed. This is made possible by the use of adouble-lead thread in the spiral channel 372.

Referring now to Figures 18 and 19, there is shown another form ofAtorque varying means which may be utilized with a transmissionconstructed in accordance with the present invention in place of thoseshown and described hereinabove. This torque varying means is of anangular Contact cam type and includes a drive sleeve member 386 which isadapted to be coupled to the input shaft 252 of a transmission such asthat shown in Figures 9 through 16 in the same manner as the drivesleeve member 360 described above. The rear portion of the drive sleevemember 386 deiines a smooth inner raceway 388 for a plurality of balls390 carried by a retainer 392. The outer raceway 394 for such balls isformed at the front portion of the input disc member 254', This outerraceway 394 includes a plurality of pockets defining cam surfaces 396which are inclined axially toward the driven disc member (not shown). Inoperation, upon the application of torque above that which will fullycompress a pre-load spring, such as that designated 385 in Figure 9, theballs will tend to cam the input disc member to the left so as toincrease the pressure of the input disc member 254 against the rollers(not shown) and through the rollers to the driven disc member (notshown). It should be particularly observed that the balls 390continually move, or walk, relative to the smooth inner raceway 388during operation `of the transmission. Accordingly, the danger of theballs causing a pitting of this raceway is minimized. Although the outerraceway 394 may become slightly wornby the balls, such wear is spreadover a greater area than would be the case with the inner raceway.Furthermore, the contact stress` of the balls will be lower on the outerraceway than on the inner raceway.

It will be understood that various modifications and changes may be madewith respect to the foregoing detailed description without departingfrom the spirit of the invention or the scope of the following claims.

I claim:

1. In a variable speed transmission, a generally'frustoconical rotarydrive member and a similar driven member, said members having opposedsurfaces of revolution, a roller bridging said surfaces of revolution,said drive and driven members having hub portions and having fluidconduits entering at said hub portions and extending outwardly to pointsadjacent the peripheries of said members, and, a iiuid supply conduithaving an inlet and an outlet, the outlet of said supply conduit beingin ow communication with said rst-mentioned conduits at said hubporti-ons, the fluid conduits in said rotary drive and driven membersbeing located immediately behind the driving contact surfaces of saidmembers and said roller.

2. A transmission comprising: a sealed casing; a driving disc memberrotatably mounted in said casing; a driven disc member opposite to andaxially spaced from said driving disc member; a roller bridging saiddriving and driven member, said driving and driven members having hubportions and having iiuid conduits entering at said hub portions andextending outwardly to points adjacent the peripheries of said members;a iiuid supply conduit having an inlet and an outlet, the outlet of saidsupply conduit being in iiow communication with said first-mentionedconduits at said hub portions; inlet means formed in said casing incommunication with said supply conduit; and outlet means formed in saidcasing in communication with said uid conduits.

3. In a variable speed transmission, a rotary driving member having aconcave surface of revolution, a rotary driven member having a concavesurface of revolution generally facing that of said driving member, andan intermediate drive-transmitting roller having a convex surface ofrevolution and bridging said driving and driven members in a position tobring its convex surface into driving contact with the concave surfacesof said driving and driven members, said driving and driven membershaving hub portions and having fiuid conduits entering at said hubportions and extending outwardly to points adjacent the peripheries ofsaid members, and, a fluid supply conduit having an inlet and an outlet,the outlet of said supply conduit being in iiow communication with saidfirst-mentioned conduits at said hub portions.

4. A transmission comprising: a frame; a driving disc member rotatablymounted by said frame; a coaxial driven disc member rotatably mounted bysaid frame, said disc members having opposed axially-spaced concavesurfaces -of revolution approximating a toric section, and at least oneof said disc members being movable axially relative to said shaft towardthe other disc member upon an increase in load being transferred throughsaid transmission; and, a conically profiled roller interposed lbetweensaid disc members and having a convex surface of revolution in drivingcontact with said concave surfaces, the Inormal radius of curvature ofsaid convex surface being smaller than that of said concave surfaceswhereby the contact path between said roller surface and said discmember surfaces will be narrower during part-load conditions than duringfull-load conditions, said roller deforming until its convex surfaceapproximates the curvature of the concave surfaces of said disc membersupon axial movement of one disc member toward another.

5. A transmission, comprising: a frame; a driving shaft rotatablymounted by said frame; a driving disc member coaxially mounted by saidshaft; a coaxial driven disc member rotatably mounted by said frameopposite to and spaced from said driving disc member; a rollerinterposed between said disc members in rotation-transmitting contacttherewith; a coaxial drive sleeve member mounted by said shaft, saidsleeve member being formed with a spiral groove; a complementary spiralgroove formed in said driving disc member sfo as to define inconjunction with the other said groove a spiral ball passage; aplurality of balls in said passage; a cross-over notch connectingadjacent threads of the spiral groove formed in said driving discmember, said notch being in part defined by a pair of scooping fingersthat guide said balls through said notch; and, means for biasing saiddrive sleeve toward said driving dise member.

6. A transmission comprising: a frame; a driving shaft rotatably mountedby said frame; a driving disc member coaxially mounted by said shaft,said disc being movable axially relative to said shaft; a coaxial drivendisc member rotatably mounted by said frame, said disc members havingopposed axially-spaced concave surfaces of revolution approximating atoric section; a roller interposed between said disc members and havinga convex surface of revolution in bridging contact with the concavesurfaces thereof; a coaxial drive sleeve member mounted by said shaft,said sleeve member being formed with a spiral groove; a complementaryspiral groove formed in said driving disc member so as to define inconjunction with the other said groove a spiral ball passage;

a plurality of balls in said passage; a crossover notch connectingadjacent threads of the spiral groove formed in said driving discmember, said notch being in part defined by a pair of scooping fingersthat guide said balls through said notch; and, spring means for biasingsaid drive sleeve toward said driving disc member.

7. A transmission comprising: a frame; a driving shaft rotatably mountedby said frame; a driving disc member coaxially mounted by said shaft; acoaxial driven disc member rotatably mounted by said frame opposite toand axially spaced from said driving disc member; a roller interposedbetween said disc members in rotation-transmitting contact therewith; acoaxial drive sleeve member mounted by said shaft, said member beingformed with a smooth inner raceway; an outer raceway formed in saiddriving disc member, said outer raceway including a plurality of pocketsdefining cam surfaces that are inclined axially; a ball disposed in eachof said pockets; and, means biasing said drive sleeve member toward saiddriving disc member.

8. A transmission comprising: a frame; a driving shaft rotatably mountedby said frame; a driving disc member coaxially mounted by said shaft,said disc being movable axially relative to said shaft; a coaxial drivendisc member rotatably mounted by said frame, said disc members havingopposed axially-spaced concave surfaces of revolution approximating atoric section; a roller interposed between said disc members and havinga convex surface in bridging contact with the concave surfaces thereof;a coaxial drive sleeve mounted by said shaft, said member being formedwith a smooth inner raceway; an outer raceway formed in said drivingdisc member, said outer raceway including a plurality of pocketsdefining cam surfaces that are inclined axially; a ball disposed in eachof said pockets, said balls -being mounted by a circular retainer; and,means baising said drive sleeve member toward said driving disc member.

9. A transmission comprising: a frame; a shaft r0- tatably mounted bysaid frame; a first disc member coaxially mounted by said shaft, saiddisc member being movable axially relative to said shaft; a second discmember coaxially rotatably mounted by said frame, said disc membershaving opposed axially-spaced concave surfaces of revolutionapproximating a toric section; a roller interposed between said discmembers and having a convex surface in bridging contact with the concavesurfaces thereof; a coaxial drive sleeve mounted by said shaft, saidsleeve being formed with a smooth inner raceway; an outer raceway formedin said first driving disc member opposite said inner raceway, saidouter raceway including a plurality of pockets defining cam surfacesthat are inclined axially towards said first disc member; a balldisposed in each of said pockets; a circular retainer for said -ballswhereby they will be free to continually move relative to said innerraceway during operation of said transmission; and means biasing saiddrive sleeve member towards said first disc member.

l0. A transmission comprising: a frame; a driving disc member rotatablymounted by said frame; a coaxial constant-speed driven disc memberrotatably mounted by said frame, said disc members having opposedaxiallyspaced concave surfaces of revolution approximating a toricsection; a conically profiled roller interposed between said discmembers and formed with a convex surface bridging the concave surfacesof said disc members; mounting means for said rollers interposed betweensaid roller and said frame; steering means for said rollers permittingsaid roller to be moved from one ratio position to another; controlmeans for moving said roller from one ratio position to anotherincluding a control ring coaxially carried by said frame and a controlarm interconnecting said roller and said control ring, said arm movingsaid roller upon partial rotation of said ring; a servomotor on saidframe and connected to said control ring lso as to effect its partialrotation; and sensing means connecting said servo motor and said drivendisc member whereby said servo motor will partially rotate said controlring responsive to a change in speed of said driven disc member.

11. A transmission comprising: a frame; a driving disc member rotatablymounted by said frame; a coaxial constant-speed driven disc memberrotatably mounted by said frame, said disc members having opposedaxiallyspaced concave surfaces of revolution approximating a toricsection; a conically proled roller interposed between said disc membersand formed with a convex surface bridging the concave surfaces vof saiddisc members; mounting means for said rollers interposed between saidroller and said frame; steering means for said roller permitting saidroller to be moved from one ratio position to another; control means formoving said roller from one ratio position to another including acontrol ring coaxially carried by said frame and a control arminterconnecting said roller and said control ring, said arm moving saidroller upon partial rotation of said ring; a servomotor on said frameand having its output shaft connected to said control ring so as toeiect its partial rotation; a rotary control shaft connected to saidservomotor; and a friction drive wheel keyed to said rotary controlshaft and having its periphery engaged with said driven disc, said servomotor being adapted to effect partial rotation of said control ringresponsive to a change in speed `of said driven disc member.

12. A transmission comprising: a frame; shaft means rotatably mounted bysaid frame; a driving disc member coaxially mounted by said shaft means;a coaxial driven disc member rotatably mounted by said shaft means, saiddisc members having opposed axially-spaced concave surfaces ofrevolution approximating a toric section, and at least `one of said discmembers being movable axially relativeto said shaft means; a conicallyproled roller interposed between said disc members and having a convexsurface in bridging contact with the concave surfaces thereof, at leastone of said members being formed With spiral groove means adapted topermit escape of liquid trapped between the contacting surfaces of saidmembers and to pump said liquid radially outwardly along said contactingsurfaces.

13. A transmission comprising: a frame; a driving disc member rotatablymounted on said frame; a coaxial constant-speed driven disc memberrotatably mounted by said frame, said disc members having opposedaxiallyspaced concave surfaces of revolution approximating a toricsection; a conically proled roller interposed between said disc membersand formed with a convex surface bridgi ing 'the concave surfaces ofsaid disc members; mounting means for said roller interposed betweensaid roller and said frame; steering means for said roller permittingsaid roller to be moved from one ratio position to another; controlmeans for steering said lroller from one ratio position to anotherincluding a control member carried by said frame and a control armconnecting said roller and said control member, said arm steering saidroller upon movement of said control member; a servomotor on said frameconnected to said control members s`o as to effect its movement; andsensing means connecting said servomotor and said driven disc memberwhereby said servomotor will eifect movement `of said control memberresponsive to a change in speed of said driven disc member.

References Cited in the le of this patent Great Britain June 4, 1952

